Argentina has given the United Kingdom two weeks to halt oil development linked to the Falkland Islands, warning that it will pursue international legal action if work on the Sea Lion project continues.
President Javier Milei instructed Argentina’s Foreign Ministry and government lawyers to begin arbitration proceedings under the United Nations Convention on the Law of the Sea. Buenos Aires says the development amounts to the exploitation of natural resources in territory and waters it considers Argentine.
The dispute centres on Sea Lion, an offshore oil project in the North Falkland Basin being developed by Israel’s Navitas Petroleum and Britain’s Rockhopper Exploration.
Milei has set a two-week deadline for the UK to prevent the start or continuation of hydrocarbon exploitation. If London does not comply, Argentina says it will seek further action through the International Tribunal for the Law of the Sea, based in Hamburg.
Sea Lion oil project raises stakes in Falklands dispute
The legal confrontation comes as Sea Lion moves closer to production, increasing the economic importance of the decades-old sovereignty dispute between Argentina and the UK.
Navitas, which operates the project, says Sea Lion is located about 220km north of the Falkland Islands. The company holds a 65% working interest, while Rockhopper owns the remaining 35%. First oil is currently planned for March 2028.
Rockhopper estimates that Sea Lion contains about 1.7 billion barrels of oil in place, with an independently assessed 500 million barrels of recoverable contingent resources previously reported for the field.
The companies have already moved beyond exploration towards development. Rockhopper and Navitas took final investment decisions on the northern development area in December 2025, while the Falkland Islands Government approved the development and production programme for the first two phases.
Rockhopper has said the project requires about $1.8 billion in funding to reach first oil and about $2.1 billion through project completion, including financing costs and contingencies.
Argentina disputes Britain’s authority to license resource development around the Falkland Islands, which it calls the Malvinas.
In its latest statement, Milei’s government cited previous United Nations resolutions concerning the sovereignty dispute and argued that unilateral exploitation of natural resources in the surrounding waters undermines Argentina’s claimed rights.
The Argentine government says the arbitration will seek to stop the Sea Lion project and prevent further permits for natural-resource development in areas it regards as part of its continental shelf.
The companies developing Sea Lion, however, operate under licences issued through the Falkland Islands authorities and have proceeded with the project on that basis. The Falkland Islands Government approved the relevant development programme in 2025.
Falklands sovereignty dispute dates back decades
The confrontation is rooted in the unresolved sovereignty dispute between Argentina and Britain over the islands, known in Argentina as the Malvinas.
Argentine forces invaded the Falklands in April 1982, triggering a 74-day war after Britain sent a military task force to retake the territory. The conflict ended with the withdrawal of Argentine forces and the continuation of British administration.
The sovereignty dispute has remained unresolved despite the end of the war.
In a 2013 referendum, Falkland Islanders voted overwhelmingly to remain a British overseas territory, with 99.8% supporting that position.
For Britain, the right of Falkland Islanders to determine their political future remains central to its position on the islands.
Oil could transform the Falklands economy
The Sea Lion development has also introduced a major economic dimension to the sovereignty dispute.
The Falkland Islands economy has traditionally relied heavily on fishing, while the development of offshore hydrocarbons offers the prospect of a new long-term source of government revenue and economic activity.
Navitas says production from Sea Lion could continue for more than 30 years and is expected to generate employment across the Falkland Islands and UK supply chains.
That economic potential has made the approaching production date particularly significant for both the island authorities and Argentina.
Argentina’s latest move therefore places a legal challenge against an oil project that has already secured investment, regulatory approvals and development plans.
For now, the next stage depends on whether Britain and the project partners respond to Buenos Aires’ two-week demand, and whether Argentina proceeds with arbitration and a potential case before the maritime tribunal.
